Grade selection:
According to the different materials to be rolled and the different characteristics of each frame, the grade of cemented carbide should be correctly selected to achieve the best matching of the grades of each frame.
Roller ring installation:
The machine should strictly lay and assemble the silver ring according to the accuracy required by the design process. The roll ring, the frame roller shaft, and the push sleeve should be properly matched. They should not be too tight or loose. When they are too tight, the roll ring is in a state of large tension.
Slightly larger rolling force fluctuations will cause the roll ring to break:
too loose will cause the roll ring and the shaft to roll. The cone sleeve causes relative sliding. The sleeve is scratched and the roll shaft is broken. When the roll ring is inserted and assembled on the machine. The assembly surfaces of the roller, shaft, and sleeve should be cleaned. It is strictly forbidden to use a hammer to knock and collide with each other during transportation and assembly.
Cooling water quality:
Cooling is to reduce the thermal corrosion of the rolling groove surface caused by high heat during rolling. Thermal fatigue cracks and thermal stress act on the roll ring to prevent the roll ring from breaking. Delay the expansion of microcracks. Extend the life of the roller ring. The cooling effect directly affects the corrosion rate of the roller ring and the rolling groove.
Cooling:
We guarantee the cooling water pressure at 46 bar. We control the water volume at more than 18m³/hour for the frame and preferably control the water volume at 24m³/hour for the last frame. The water spray should be radial, at an angle of 15~30 degrees to the direction of rotation of the roller ring. Do not scatter or mist the water. Spray it directly into the rolling groove.
Groove grinding:
It is difficult to avoid micro-cracks in the roller ring groove during rolling. When the groove micro-cracks reach a certain depth (generally controlled at about 0.02mm) during rolling, it is necessary to remove and grind them in time to reduce and avoid the continued expansion of micro-cracks in the groove and cause roll breakage.
When rebuilding the groove, you must completely grind away the micro-cracks. Otherwise, any remaining micro-cracks will pose a significant risk of roll breakage in the next rolling.
Under normal process rolling volume, we generally control grinding to 0.40.6mm for the rear rack and 0.71.2mm for the front rack.
Rolling load:
Each finishing mill has a correspondingly designed carbide roller ring and assembly form, and its size and shape have different requirements. The design load is generally 3 to 4 times the normal use load. However, the tensile strength of carbide is relatively low. A large load can destroy the fixing of the tapered sleeve and the shaft to the roller ring, and produce a large local tensile stress to cause the roller ring to rupture.
Possible factors that cause stress:
- The fit between the roller ring, the tapered sleeve, and the roller shaft is too tight: If the fit is too loose, it will cause sliding and damage to the sleeve and roller shaft, causing local deformation and large tension.
- Rolling low-temperature steel.
- Steel piling during rolling, etc.
For more information or to discuss your specific needs, contact us today! Our team is ready to assist you.
Email：cykc@cykcgroup.com.cn
Website：https://cykcgroup.com/product/cemented-tungsten-carbide-mill-rolls/